ia64/xen-unstable

view tools/ioemu/path.c @ 8740:3d7ea7972b39

Update patches for linux 2.6.15.

Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
author cl349@firebug.cl.cam.ac.uk
date Thu Feb 02 17:16:00 2006 +0000 (2006-02-02)
parents 8e5fc5fe636c
children
line source
1 /* Code to mangle pathnames into those matching a given prefix.
2 eg. open("/lib/foo.so") => open("/usr/gnemul/i386-linux/lib/foo.so");
4 The assumption is that this area does not change.
5 */
6 #include <sys/types.h>
7 #include <dirent.h>
8 #include <unistd.h>
9 #include <stdlib.h>
10 #include <string.h>
11 #include <errno.h>
12 #include <stdio.h>
13 #include "qemu.h"
15 struct pathelem
16 {
17 /* Name of this, eg. lib */
18 char *name;
19 /* Full path name, eg. /usr/gnemul/x86-linux/lib. */
20 char *pathname;
21 struct pathelem *parent;
22 /* Children */
23 unsigned int num_entries;
24 struct pathelem *entries[0];
25 };
27 static struct pathelem *base;
29 /* First N chars of S1 match S2, and S2 is N chars long. */
30 static int strneq(const char *s1, unsigned int n, const char *s2)
31 {
32 unsigned int i;
34 for (i = 0; i < n; i++)
35 if (s1[i] != s2[i])
36 return 0;
37 return s2[i] == 0;
38 }
40 static struct pathelem *add_entry(struct pathelem *root, const char *name);
42 static struct pathelem *new_entry(const char *root,
43 struct pathelem *parent,
44 const char *name)
45 {
46 struct pathelem *new = malloc(sizeof(*new));
47 new->name = strdup(name);
48 asprintf(&new->pathname, "%s/%s", root, name);
49 new->num_entries = 0;
50 return new;
51 }
53 #define streq(a,b) (strcmp((a), (b)) == 0)
55 static struct pathelem *add_dir_maybe(struct pathelem *path)
56 {
57 DIR *dir;
59 if ((dir = opendir(path->pathname)) != NULL) {
60 struct dirent *dirent;
62 while ((dirent = readdir(dir)) != NULL) {
63 if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){
64 path = add_entry(path, dirent->d_name);
65 }
66 }
67 closedir(dir);
68 }
69 return path;
70 }
72 static struct pathelem *add_entry(struct pathelem *root, const char *name)
73 {
74 root->num_entries++;
76 root = realloc(root, sizeof(*root)
77 + sizeof(root->entries[0])*root->num_entries);
79 root->entries[root->num_entries-1] = new_entry(root->pathname, root, name);
80 root->entries[root->num_entries-1]
81 = add_dir_maybe(root->entries[root->num_entries-1]);
82 return root;
83 }
85 /* This needs to be done after tree is stabalized (ie. no more reallocs!). */
86 static void set_parents(struct pathelem *child, struct pathelem *parent)
87 {
88 unsigned int i;
90 child->parent = parent;
91 for (i = 0; i < child->num_entries; i++)
92 set_parents(child->entries[i], child);
93 }
95 void init_paths(const char *prefix)
96 {
97 if (prefix[0] != '/' ||
98 prefix[0] == '\0' ||
99 !strcmp(prefix, "/"))
100 return;
102 base = new_entry("", NULL, prefix+1);
103 base = add_dir_maybe(base);
104 if (base->num_entries == 0) {
105 free (base);
106 base = NULL;
107 } else {
108 set_parents(base, base);
109 }
110 }
112 /* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */
113 static const char *
114 follow_path(const struct pathelem *cursor, const char *name)
115 {
116 unsigned int i, namelen;
118 name += strspn(name, "/");
119 namelen = strcspn(name, "/");
121 if (namelen == 0)
122 return cursor->pathname;
124 if (strneq(name, namelen, ".."))
125 return follow_path(cursor->parent, name + namelen);
127 if (strneq(name, namelen, "."))
128 return follow_path(cursor, name + namelen);
130 for (i = 0; i < cursor->num_entries; i++)
131 if (strneq(name, namelen, cursor->entries[i]->name))
132 return follow_path(cursor->entries[i], name + namelen);
134 /* Not found */
135 return NULL;
136 }
138 /* Look for path in emulation dir, otherwise return name. */
139 const char *path(const char *name)
140 {
141 /* Only do absolute paths: quick and dirty, but should mostly be OK.
142 Could do relative by tracking cwd. */
143 if (!base || name[0] != '/')
144 return name;
146 return follow_path(base, name) ?: name;
147 }